A nurse conducted a sexual assault exam on a 4-year-old girl in 2015 and police — as has happened repeatedly throughout the country — never submitted the DNA evidence to the lab for testing.

Now the girl's mother is questioning that decision by the Cumberland Police Department, saying she may never know if her ex-husband sexually abused her daughter.

The Indiana Department of Child Services doesn't think so. Police don't think so. And the father, who has been granted custody of the child, vehemently denies any abuse.

But the scientific evidence that might have helped clear or implicate him was never tested.

The Anderson mother's frustration comes as Indiana State Police conduct a statewide audit of untested sexual assault kits to determine why many are not being tested.

Although the case is unusual, because it involves such a young child, it sheds light on a national problem that prompted a National Institute of Justice report to recommend all sexual assault kits reported to law enforcement be submitted to a laboratory for DNA analysis.

More than 175,000 sexual assault kits nationwide have never been tested, according to "End the Backlog," a program of the Joyful Heart Foundation. At least 5,000 kits in Indiana have not been tested.

Like many sexual abuse complaints, the Indiana case involving the 4-year-old is contentious. The girl's mother and father have been involved in an ongoing custody battle, and accusations have been flying.

By not testing the kit, public officials missed an opportunity for an answer backed by scientific evidence. Police and welfare officials, who generally run concurrent but separate child abuse investigations, view the decision differently.

Detective Suzanne Woodland said Cumberland police in part decided not to submit the 4-year-old's sexual assault kit for testing because DCS did not substantiate abuse.

But a DCS official told IndyStar that any evidence — especially that collected by a medical professional — would help DCS make an assessment.

The bottom line: Police destroyed the evidence.

"Something just doesn’t feel right," the mother said.

IndyStar is not naming the girl or her family members because she is an alleged victim of sexual abuse.

The little girl told at least four people, including a sexual assault nurse examiner and Department of Child Services family case manager, that her father had inappropriately touched her vagina, according to DCS and medical records obtained by IndyStar.

The 4-year-old initially disclosed the alleged abuse in October 2015 to an adult, who called DCS, state records show. Child welfare officials initiated an investigation and recommended the girl's mother take her to the emergency room.

Medical officials sent them to the Community Hospital Anderson Sexual Assault Treatment Center, where a nurse did a sexual assault kit on the little girl — a relatively rare occurrence for a child that young.

When collecting evidence for a kit, medical personnel may gather clothing, fingernail scrapings and swabs from various parts of an individual’s body. It's a comprehensive exam that can take hours.

Holly Renz, the sexual assault nurse examiner who collected evidence for the girl's kit, said they typically don't collect kits on children that young because the alleged abuse must have occurred within 72 hours for there to be viable samples. Most children don't disclose within that window because they are told not to tell anyone, she said.

Renz collected the kit on the 4-year-old because there wasn't a clear time reference and the mother, based on what DCS told her, said the abuse may have occurred the night before, according to medical records.

The Anderson woman said watching her daughter get that sexual assault kit taken was "an image you can't forget."

"There's no words to describe how horrible that was to be there with her, to go through that with her," the woman said. "It's horrible to hear her talk about it. That’s not anything you want your child to go through. Ever."

The 4-year-old told Renz that her father touched her "girl parts" with his finger, according to medical records. "It hurts," she said.

The girl also was interviewed later that day by a trained forensic interviewer while a deputy prosecutor, victim's advocate and DCS family case manager watched from an observation room.

During the forensic interview, the girl said her dad "touches her down there in her bedroom," according to DCS records. She said her father "keeps his hand still when he touches her and it hurts very very bad, and that it happens over her clothes," DCS records state. The 4-year-old could not provide further details during the interview.

The initial DCS report said the girl claimed her father touched her while she was being bathed.

After interviewing six people, DCS unsubstantiated the sexual abuse allegation "due to a lack of a preponderance of evidence," records show. It noted the 4-year-old "did not disclose any reliable information of sexual abuse" during the forensic interview.

The girl's father denied any inappropriate conduct involving his daughter. He told IndyStar it was a false report, one of many orchestrated by his ex-wife, who was angry because a judge gave him custody of their children.

"People like her tie the system up," he said.

DCS has received at least 16 reports of alleged neglect, physical abuse or sexual abuse relating to the family since 2012, state records show. None of those allegations was substantiated.

"This is an issue between mom and dad due to the dad having custody," said Woodland, the Cumberland police detective who handled the criminal investigation.

After DCS unsubstantiated the claim, Woodland said, the police department did not test the kit because to do so would be "a waste of the lab's time." She said the department had the sexual assault kit destroyed.

The girl's mother said she is "unnerved" that the department chose to destroy the sexual assault kit. She said it could have helped answer that question of who, if anyone, sexually abused her daughter, now 6.

"If a kit was completed, it should have been tested," the mother said, echoing others who advocate for testing all sexual assault kits. "An officer should not outrank a parent who’s concerned."